First, prepare the sauce. In a small bowl, combine soy sauce, brown sugar, sesame oil, rice vinegar, chili oil, oyster sauce, and powdered ginger. Whisk thoroughly until fully combined.
Preheat a wok over medium-high heat, then add the butter, swirling it around to help it melt.
Once the butter is fully melted, add minced garlic to the wok and cook until fragrant, about 1 to 2 minutes, moving it around to prevent sticking. If you hear a lot of sizzling right away, you may have to lower the heat so the garlic doesn't burn.
Pour the sauce into the wok and stir or swirl to incorporate the minced garlic and butter evenly with the sauce. Then add the udon and stir fry until steaming and noodles are warmed through, about 3 to 5 minutes.
Season with a pinch of salt and white pepper, tossing the noodles to combine. Then stir in sliced scallions and remove from heat. Serve immediately.
Notes
Japanese udon: Look for the cooked, prepackaged udon in vacuum sealed packs at the store. These chubby noodles are the perfect vehicle for this savory, garlicky sauce! If you can't find them, this recipe also works well with Chinese lo mein noodles. Simply cook your choice of noodles according to the package directions before adding to the wok and stir frying.Fresh garlic: This recipe absolutely needs a fresh head of garlic. Mincing a whole head of garlic can feel like a lot of work, but we guarantee it's worth it! We tried making this dish with jarred minced garlic and found it wasn't sticky enough to incorporate well with the sauce and noodles - more than half of it ended up in the bottom of the wok and there wasn't nearly enough garlic flavor in the final dish.Cooking with a wok: If you've never used a wok before, it can be tricky. Check out our blog post above for some helpful best practices. If you don't have a wok, this recipe can also be made in a large nonstick saute pan.